Within the last 50 years the light and specially the laser has fomented great advances in several areas of science and technology. During the past decade the use of optical stimuli in the biomedical research field have been of great interest for both academy and industry. Two research branches that can be highlighted due to its growth are: direct optical stimulation and optogenetic. The first one uses different parameters of light to optimize the desired effect on the tissue interaction. The other branch works with genetic engineering technics to make cells sensitive to light. The neural stimulation by infrared (direct optical stimulation) does not require direct contact with the tissue and has higher spatial selectivity when compared to electrical stimulation, but it has restricted ability to activate (depolarize) neurons. The optogenetic, however, can be used to manipulate the neural tissue depolarizing or hyperpolarizing encoded neurons, as well as monitor activations by encoding fluorescent proteins sensitive to voltage. The stimulation by infrared optical or optogenetic, has been applied only to animal models although there is a great possibility for human applications. In the future, it may even replace existing techniques such as electrical brain stimulation to treat specific neurological diseases.
Optogenetic; Optical stimulation of neural tissue; Photoreceptors
